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<div id="overview"><a href="../../../../../apidocs/org/apache/torque/util/JoinBuilder.html">View Javadoc</a></div><pre>

<a name="1" href="#1">1</a>   <strong>package</strong> <a href="../../../../org/apache/torque/util/package-summary.html">org.apache.torque.util</a>;
<a name="2" href="#2">2</a>   
<a name="3" href="#3">3</a>   <em class="comment">/*</em>
<a name="4" href="#4">4</a>   <em class="comment"> * Licensed to the Apache Software Foundation (ASF) under one</em>
<a name="5" href="#5">5</a>   <em class="comment"> * or more contributor license agreements.  See the NOTICE file</em>
<a name="6" href="#6">6</a>   <em class="comment"> * distributed with this work for additional information</em>
<a name="7" href="#7">7</a>   <em class="comment"> * regarding copyright ownership.  The ASF licenses this file</em>
<a name="8" href="#8">8</a>   <em class="comment"> * to you under the Apache License, Version 2.0 (the</em>
<a name="9" href="#9">9</a>   <em class="comment"> * "License"); you may not use this file except in compliance</em>
<a name="10" href="#10">10</a>  <em class="comment"> * with the License.  You may obtain a copy of the License at</em>
<a name="11" href="#11">11</a>  <em class="comment"> *</em>
<a name="12" href="#12">12</a>  <em class="comment"> *   <a href="http://www.apache.org/licenses/LICENSE-2.0" target="alexandria_uri">http://www.apache.org/licenses/LICENSE-2.0</a></em>
<a name="13" href="#13">13</a>  <em class="comment"> *</em>
<a name="14" href="#14">14</a>  <em class="comment"> * Unless required by applicable law or agreed to in writing,</em>
<a name="15" href="#15">15</a>  <em class="comment"> * software distributed under the License is distributed on an</em>
<a name="16" href="#16">16</a>  <em class="comment"> * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY</em>
<a name="17" href="#17">17</a>  <em class="comment"> * KIND, either express or implied.  See the License for the</em>
<a name="18" href="#18">18</a>  <em class="comment"> * specific language governing permissions and limitations</em>
<a name="19" href="#19">19</a>  <em class="comment"> * under the License.</em>
<a name="20" href="#20">20</a>  <em class="comment"> */</em>
<a name="21" href="#21">21</a>  
<a name="22" href="#22">22</a>  <strong>import</strong> java.util.List;
<a name="23" href="#23">23</a>  
<a name="24" href="#24">24</a>  <strong>import</strong> org.apache.torque.TorqueException;
<a name="25" href="#25">25</a>  <strong>import</strong> org.apache.torque.adapter.DB;
<a name="26" href="#26">26</a>  <strong>import</strong> org.apache.torque.map.DatabaseMap;
<a name="27" href="#27">27</a>  
<a name="28" href="#28">28</a>  <em>/**<em>*</em></em>
<a name="29" href="#29">29</a>  <em> * Factored out code that is used to generate Join Code. This code comes</em>
<a name="30" href="#30">30</a>  <em> * from BasePeer and is put here to reduce complexity in the BasePeer class.</em>
<a name="31" href="#31">31</a>  <em> * You should not use the methods here directly!</em>
<a name="32" href="#32">32</a>  <em> *</em>
<a name="33" href="#33">33</a>  <em> * @author &lt;a href="<a href="mailto:fischer@seitenbau.de" target="alexandria_uri">mailto:fischer@seitenbau.de</a>">Thomas Fischer&lt;/a></em>
<a name="34" href="#34">34</a>  <em> * @author &lt;a href="<a href="mailto:hps@intermeta.de" target="alexandria_uri">mailto:hps@intermeta.de</a>">Henning P. Schmiedehausen&lt;/a></em>
<a name="35" href="#35">35</a>  <em> * @version $Id: JoinBuilder.java 535615 2007-05-06 14:11:05Z tv $</em>
<a name="36" href="#36">36</a>  <em> */</em>
<a name="37" href="#37">37</a>  <strong>public</strong> <strong>final</strong> <strong>class</strong> <a href="../../../../org/apache/torque/util/JoinBuilder.html">JoinBuilder</a>
<a name="38" href="#38">38</a>  {
<a name="39" href="#39">39</a>      <em>/**<em>*</em></em>
<a name="40" href="#40">40</a>  <em>     * Private constructor to prevent initialisation.</em>
<a name="41" href="#41">41</a>  <em>     *</em>
<a name="42" href="#42">42</a>  <em>     * Class contains only static methods and should therefore not be</em>
<a name="43" href="#43">43</a>  <em>     * instantiated.</em>
<a name="44" href="#44">44</a>  <em>     */</em>
<a name="45" href="#45">45</a>      <strong>private</strong> <a href="../../../../org/apache/torque/util/JoinBuilder.html">JoinBuilder</a>()
<a name="46" href="#46">46</a>      {
<a name="47" href="#47">47</a>      }
<a name="48" href="#48">48</a>  
<a name="49" href="#49">49</a>      <em>/**<em>*</em></em>
<a name="50" href="#50">50</a>  <em>     * adds the Joins from the criteria to the query</em>
<a name="51" href="#51">51</a>  <em>     * @param criteria the criteria from which the Joins are taken</em>
<a name="52" href="#52">52</a>  <em>     * @param query the query to which the Joins should be added</em>
<a name="53" href="#53">53</a>  <em>     * @throws TorqueException if the Joins can not be processed</em>
<a name="54" href="#54">54</a>  <em>     */</em>
<a name="55" href="#55">55</a>      <strong>public</strong> <strong>static</strong> <strong>void</strong> processJoins(
<a name="56" href="#56">56</a>              <strong>final</strong> <a href="../../../../org/apache/torque/adapter/DB.html">DB</a> db,
<a name="57" href="#57">57</a>              <strong>final</strong> <a href="../../../../org/apache/torque/map/DatabaseMap.html">DatabaseMap</a> dbMap,
<a name="58" href="#58">58</a>              <strong>final</strong> <a href="../../../../org/apache/torque/util/Criteria.html">Criteria</a> criteria,
<a name="59" href="#59">59</a>              <strong>final</strong> <a href="../../../../org/apache/torque/util/Query.html">Query</a> query)
<a name="60" href="#60">60</a>              throws <a href="../../../../org/apache/torque/TorqueException.html">TorqueException</a>
<a name="61" href="#61">61</a>      {
<a name="62" href="#62">62</a>          List criteriaJoins = criteria.getJoins();
<a name="63" href="#63">63</a>  
<a name="64" href="#64">64</a>          <strong>if</strong> (criteriaJoins.isEmpty())
<a name="65" href="#65">65</a>          {
<a name="66" href="#66">66</a>              <strong>return</strong>;
<a name="67" href="#67">67</a>          }
<a name="68" href="#68">68</a>  
<a name="69" href="#69">69</a>          <a href="../../../../org/apache/torque/util/UniqueList.html">UniqueList</a> queryFromClause = query.getFromClause();
<a name="70" href="#70">70</a>          <a href="../../../../org/apache/torque/util/UniqueList.html">UniqueList</a> queryWhereClause = query.getWhereClause();
<a name="71" href="#71">71</a>  
<a name="72" href="#72">72</a>          <strong>for</strong> (<strong>int</strong> i = 0; i &lt; criteriaJoins.size(); i++)
<a name="73" href="#73">73</a>          {
<a name="74" href="#74">74</a>              Criteria.Join join = (Criteria.Join) criteriaJoins.get(i);
<a name="75" href="#75">75</a>              String leftColumn = join.getLeftColumn();
<a name="76" href="#76">76</a>              String rightColumn = join.getRightColumn();
<a name="77" href="#77">77</a>  
<a name="78" href="#78">78</a>              <em class="comment">// check if the column names make sense</em>
<a name="79" href="#79">79</a>              <strong>if</strong> (leftColumn.indexOf('.') == -1)
<a name="80" href="#80">80</a>              {
<a name="81" href="#81">81</a>                  SQLBuilder.throwMalformedColumnNameException(<span class="string">"join"</span>, leftColumn);
<a name="82" href="#82">82</a>              }
<a name="83" href="#83">83</a>              <strong>if</strong> (rightColumn.indexOf('.') == -1)
<a name="84" href="#84">84</a>              {
<a name="85" href="#85">85</a>                  SQLBuilder.throwMalformedColumnNameException(<span class="string">"join"</span>, rightColumn);
<a name="86" href="#86">86</a>              }
<a name="87" href="#87">87</a>  
<a name="88" href="#88">88</a>              <em class="comment">// get the table names</em>
<a name="89" href="#89">89</a>              <em class="comment">// (and the alias names for them if necessary))</em>
<a name="90" href="#90">90</a>              <em class="comment">// Also check whether a case insensitive comparison is needed</em>
<a name="91" href="#91">91</a>              <strong>int</strong> dot = leftColumn.lastIndexOf('.');
<a name="92" href="#92">92</a>              String leftTableName = leftColumn.substring(0, dot);
<a name="93" href="#93">93</a>  
<a name="94" href="#94">94</a>              leftTableName =
<a name="95" href="#95">95</a>                      SQLBuilder.getTableNameForFromClause(leftTableName, criteria);
<a name="96" href="#96">96</a>  
<a name="97" href="#97">97</a>              dot = rightColumn.lastIndexOf('.');
<a name="98" href="#98">98</a>              String rightTableName = rightColumn.substring(0, dot);
<a name="99" href="#99">99</a>              String dbTableName
<a name="100" href="#100">100</a>                     = criteria.getTableForAlias(rightTableName);
<a name="101" href="#101">101</a> 
<a name="102" href="#102">102</a>             <strong>if</strong> (dbTableName == <strong>null</strong>)
<a name="103" href="#103">103</a>             {
<a name="104" href="#104">104</a>                 dbTableName = rightTableName;
<a name="105" href="#105">105</a>             }
<a name="106" href="#106">106</a> 
<a name="107" href="#107">107</a>             String columnName = rightColumn.substring(
<a name="108" href="#108">108</a>                     dot + 1,
<a name="109" href="#109">109</a>                     rightColumn.length());
<a name="110" href="#110">110</a> 
<a name="111" href="#111">111</a>             <strong>boolean</strong> ignoreCase = (criteria.isIgnoreCase()
<a name="112" href="#112">112</a>                     &amp;&amp; (dbMap
<a name="113" href="#113">113</a>                             .getTable(dbTableName)
<a name="114" href="#114">114</a>                             .getColumn(columnName)
<a name="115" href="#115">115</a>                             .getType()
<a name="116" href="#116">116</a>                             instanceof String));
<a name="117" href="#117">117</a> 
<a name="118" href="#118">118</a>             rightTableName = SQLBuilder.getTableNameForFromClause(
<a name="119" href="#119">119</a>                     rightTableName, criteria);
<a name="120" href="#120">120</a> 
<a name="121" href="#121">121</a>             <em class="comment">// now check the join type and add the join to the</em>
<a name="122" href="#122">122</a>             <em class="comment">// appropriate places in the query</em>
<a name="123" href="#123">123</a>             <a href="../../../../org/apache/torque/util/SqlEnum.html">SqlEnum</a> joinType  = join.getJoinType();
<a name="124" href="#124">124</a> 
<a name="125" href="#125">125</a>             <strong>if</strong> (joinType == <strong>null</strong>)
<a name="126" href="#126">126</a>             {
<a name="127" href="#127">127</a>                 <em class="comment">// Do not treat join as explicit join, but add</em>
<a name="128" href="#128">128</a>                 <em class="comment">// the join condition to the where clauses</em>
<a name="129" href="#129">129</a>                 <strong>if</strong> (!SQLBuilder.fromClauseContainsTableName(
<a name="130" href="#130">130</a>                             queryFromClause,
<a name="131" href="#131">131</a>                             leftTableName))
<a name="132" href="#132">132</a>                 {
<a name="133" href="#133">133</a>                     Query.FromElement fromElement
<a name="134" href="#134">134</a>                             = <strong>new</strong> Query.FromElement(
<a name="135" href="#135">135</a>                                     leftTableName, <strong>null</strong>, <strong>null</strong>);
<a name="136" href="#136">136</a>                     queryFromClause.add(fromElement);
<a name="137" href="#137">137</a>                 }
<a name="138" href="#138">138</a>                 <strong>if</strong> (!SQLBuilder.fromClauseContainsTableName(
<a name="139" href="#139">139</a>                             queryFromClause,
<a name="140" href="#140">140</a>                             rightTableName))
<a name="141" href="#141">141</a>                 {
<a name="142" href="#142">142</a>                     Query.FromElement fromElement
<a name="143" href="#143">143</a>                             = <strong>new</strong> Query.FromElement(
<a name="144" href="#144">144</a>                                     rightTableName, <strong>null</strong>, <strong>null</strong>);
<a name="145" href="#145">145</a>                     queryFromClause.add(fromElement);
<a name="146" href="#146">146</a>                 }
<a name="147" href="#147">147</a>                 queryWhereClause.add(
<a name="148" href="#148">148</a>                         SqlExpression.buildInnerJoin(
<a name="149" href="#149">149</a>                                 leftColumn, rightColumn, ignoreCase, db));
<a name="150" href="#150">150</a>             }
<a name="151" href="#151">151</a>             <strong>else</strong>
<a name="152" href="#152">152</a>             {
<a name="153" href="#153">153</a>                 <em class="comment">// check whether the order of the join must be "reversed"</em>
<a name="154" href="#154">154</a>                 <em class="comment">// This if the case if the fromClause already contains</em>
<a name="155" href="#155">155</a>                 <em class="comment">// rightTableName</em>
<a name="156" href="#156">156</a> 
<a name="157" href="#157">157</a>                 <strong>if</strong> (!SQLBuilder.fromClauseContainsTableName(
<a name="158" href="#158">158</a>                             queryFromClause,
<a name="159" href="#159">159</a>                             rightTableName))
<a name="160" href="#160">160</a>                 {
<a name="161" href="#161">161</a>                     <strong>if</strong> (!SQLBuilder.fromClauseContainsTableName(
<a name="162" href="#162">162</a>                                 queryFromClause,
<a name="163" href="#163">163</a>                                 leftTableName))
<a name="164" href="#164">164</a>                     {
<a name="165" href="#165">165</a>                         Query.FromElement fromElement
<a name="166" href="#166">166</a>                                 = <strong>new</strong> Query.FromElement(
<a name="167" href="#167">167</a>                                         leftTableName, <strong>null</strong>, <strong>null</strong>);
<a name="168" href="#168">168</a>                         queryFromClause.add(fromElement);
<a name="169" href="#169">169</a>                     }
<a name="170" href="#170">170</a> 
<a name="171" href="#171">171</a>                     Query.FromElement fromElement
<a name="172" href="#172">172</a>                             = <strong>new</strong> Query.FromElement(
<a name="173" href="#173">173</a>                                     rightTableName, joinType,
<a name="174" href="#174">174</a>                                     SqlExpression.buildInnerJoin(
<a name="175" href="#175">175</a>                                             leftColumn, rightColumn,
<a name="176" href="#176">176</a>                                             ignoreCase, db));
<a name="177" href="#177">177</a>                     queryFromClause.add(fromElement);
<a name="178" href="#178">178</a>                 }
<a name="179" href="#179">179</a>                 <strong>else</strong>
<a name="180" href="#180">180</a>                 {
<a name="181" href="#181">181</a>                     <strong>if</strong> (SQLBuilder.fromClauseContainsTableName(
<a name="182" href="#182">182</a>                                 queryFromClause,
<a name="183" href="#183">183</a>                                 leftTableName))
<a name="184" href="#184">184</a>                     {
<a name="185" href="#185">185</a>                         <em class="comment">// We cannot add an explicit join if both tables</em>
<a name="186" href="#186">186</a>                         <em class="comment">// are alredy present in the from clause</em>
<a name="187" href="#187">187</a>                         <strong>throw</strong> <strong>new</strong> <a href="../../../../org/apache/torque/TorqueException.html">TorqueException</a>(
<a name="188" href="#188">188</a>                                 <span class="string">"Unable to create a "</span> + joinType
<a name="189" href="#189">189</a>                                 + <span class="string">"because both table names "</span>
<a name="190" href="#190">190</a>                                 + leftTableName + <span class="string">" and "</span> + rightTableName
<a name="191" href="#191">191</a>                                 + <span class="string">" are already in use. "</span>
<a name="192" href="#192">192</a>                                 + <span class="string">"Try to create an(other) alias."</span>);
<a name="193" href="#193">193</a>                     }
<a name="194" href="#194">194</a>                     <em class="comment">// now add the join in reverse order</em>
<a name="195" href="#195">195</a>                     <em class="comment">// rightTableName must not be added</em>
<a name="196" href="#196">196</a>                     <em class="comment">// because it is already present</em>
<a name="197" href="#197">197</a>                     Query.FromElement fromElement
<a name="198" href="#198">198</a>                             = <strong>new</strong> Query.FromElement(
<a name="199" href="#199">199</a>                                     leftTableName, reverseJoinType(joinType),
<a name="200" href="#200">200</a>                                     SqlExpression.buildInnerJoin(
<a name="201" href="#201">201</a>                                             rightColumn, leftColumn,
<a name="202" href="#202">202</a>                                             ignoreCase, db));
<a name="203" href="#203">203</a>                     queryFromClause.add(fromElement);
<a name="204" href="#204">204</a>                 }
<a name="205" href="#205">205</a>             }
<a name="206" href="#206">206</a>         }
<a name="207" href="#207">207</a>     }
<a name="208" href="#208">208</a> 
<a name="209" href="#209">209</a>     <em>/**<em>*</em></em>
<a name="210" href="#210">210</a> <em>     * returns the reversed Join type, i.e. the join type which would produce</em>
<a name="211" href="#211">211</a> <em>     * the same result if also the joined tables were exchanged:</em>
<a name="212" href="#212">212</a> <em>     * Example:&lt;br /></em>
<a name="213" href="#213">213</a> <em>     * table_a left join table_b &lt;br /></em>
<a name="214" href="#214">214</a> <em>     * produces the same result as  &lt;br /></em>
<a name="215" href="#215">215</a> <em>     * table_b right join table_a&lt;br /></em>
<a name="216" href="#216">216</a> <em>     * So "left join" is the reverse of "right join"</em>
<a name="217" href="#217">217</a> <em>     * @param joinType the join type to be reversed</em>
<a name="218" href="#218">218</a> <em>     * @return the reversed join type</em>
<a name="219" href="#219">219</a> <em>     */</em>
<a name="220" href="#220">220</a>     <strong>private</strong> <strong>static</strong> <a href="../../../../org/apache/torque/util/SqlEnum.html">SqlEnum</a> reverseJoinType(<strong>final</strong> <a href="../../../../org/apache/torque/util/SqlEnum.html">SqlEnum</a> joinType)
<a name="221" href="#221">221</a>     {
<a name="222" href="#222">222</a>         <strong>if</strong> (SqlEnum.LEFT_JOIN.equals(joinType))
<a name="223" href="#223">223</a>         {
<a name="224" href="#224">224</a>             <strong>return</strong> SqlEnum.RIGHT_JOIN;
<a name="225" href="#225">225</a>         }
<a name="226" href="#226">226</a>         <strong>else</strong> <strong>if</strong> (SqlEnum.RIGHT_JOIN.equals(joinType))
<a name="227" href="#227">227</a>         {
<a name="228" href="#228">228</a>             <strong>return</strong> SqlEnum.LEFT_JOIN;
<a name="229" href="#229">229</a>         }
<a name="230" href="#230">230</a>         <strong>else</strong>
<a name="231" href="#231">231</a>         {
<a name="232" href="#232">232</a>             <strong>return</strong> joinType;
<a name="233" href="#233">233</a>         }
<a name="234" href="#234">234</a>     }
<a name="235" href="#235">235</a> }
</pre>
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